256 THE ORIGIN OF SPECIES 



short, or what its precise features will he. The question 

 is not, at what period of life each variation may have 

 been caused, but at what period the effects are displayed. 

 The cause may have acted, and I believe often has 

 acted, on one or both parents before the act of genera- 

 tion. It deserves notice that it is of no importance to a 

 very young animal, as long as it remains in its mother's 

 womb or in the egg, or as long as it is nourished and 

 protected by its parent, whether most of its characters 

 are acquired a little earlier or later in life. It would not 

 signify, for instance, to a bird which obtained its food 

 b}' having a much-curved beak whether or not while 

 young it possessed a beak of this shape, as long as it 

 was fed by its parents. 



I have stated, in the first chapter, that at whatever 

 age a variation first appears in the parent, it tends to 

 reappear at a corresponding age in the offspring. Certain 

 variations can only appear at corresponding ages; for 

 instance, peculiarities in the caterpillar, cocoon, or imago 

 states of the silk-moth: or, again, in the full-grown 

 horns of cattle. But variations, which, for all that we 

 can see might have first appeared either earlier or later 

 in life, likewise tend to reappear at a corresponding 

 age in the offspring and parent, i am far from meaning 

 that this is invariably the case, and I could give several 

 exceptional cases of variations (taking the word in the 

 largest sense) which have supervened at an earlier age in 

 the child than in the parent. 



These two principles, namely, that slight variations 

 generally appear at a not very early period of life, and 

 are inherited at a corresponding not early period, explain, 

 as I believe, all the above specified leading facts in em- 



